Yam, Kit L. (ed.). The Wiley encyclopedia of packaging technology

Подождите немного. Документ загружается.

possible to develop special pressure-sensitive tapes for

many packaging uses, including combining and tamper

evidence. Tapes are used to attach and protect labels on

packages. Tape pouches often enclose packing lists and

documents for shipment (see also Tape, gummed).

Several tapes are available not only on traditional

rolls but also in precut pads (Figure 4). These pads

provide for the use of presized pieces of tape for covering

labels, attaching documents, and closing packages. They

do not require a dispenser and offer the advantage of

portability.

ENVIRONMENTAL CONSIDERATIONS

The environmental considerations for tapes applied to

boxes are given in ASTM D1974. Pressure-sensitive tapes

are often a good method of source reduction, considered to

be a primary objective in reducing the contribution of

packaging to municipal solid waste. Box-closure tapes

often use less materials than alternative closures. Small

L-clips of tape can close folding cartons, replacing a shrink

overwrap and reducing material usage.

Compatibility with recycling operations for larger

package components is important. For box recycling,

pressure-sensitive tapes do not have to be removed from

corrugated boxes prior to recycling operations. When a

tape has a water-resistant tape backing, the adhesive

stays with the backing in the hydropulper. The tape is

easily removed intact by normal pulp-cleaning processes;

neither the recycling paper nor recycling water is con-

taminated by the tape. When corrugated boxes are re-

cycled, ﬁlm-backed box sealing tapes do not hinder box

recycling: The PSA tape stays with backing and is easily

removed (4).

Stretchable LLDPE tapes are available for pallet uni-

tizing, offering source reduction from full stretch wraps.

When the tape is used in conjunction with stretch wrap, it

is compatible with the stretch-wrap recycling operations

(see also Recycling; Environmental laws, International

and North America).

Pressure-sensitive tape is a versatile packaging mate-

rial that can offer cost savings, productivity improve-

ments, and source reductions. Innovations beneﬁcial to

packagers will continue.

BIBLIOGRAPHY

R. L. Sheehan, ‘‘Tape, Pressure-Sensitive’’ in The Wiley Encyclo-

pedia of Packaging, 2nd edition, John Wiley & Sons, New York,

1997, pp. 883–887.

Cited Publications

1. Pressue Sensitive Adhesive Tape, Pressure Sensitive Tape

Council, Chicago, May 2008.

2. Test Methods for Pressure Sensitive Adhesive Tapes, 15th

edition, Pressure Sensitive Tape Council, Chicago, 2007.

3. D. W. Aubrey, ‘‘Pressure-sensitive Adhesives’’ in D. E. Pack-

ham, Handbook of Adhesion, John Wiley & Sons, Chichester,

2005.

4. T. Jensen, Packaging Tapes: To Recycle or Not, Adhesives and

Sealants Council, April 1999.

TESTING CONSUMER PACKAGES FOR

MARKETING EFFECTIVENESS

LORNA OPATOW

Opatow Associates, New York,

New York

Primary and secondary packaging techniques are the key

to marketing success in bringing brands from production,

through distribution and selection by end users, and in

generating the levels of satisfaction that warrant repeat

purchase. Survey research is used to help those involved

in package development make the informed choices that

result in a marketing success.

Many package-performance dimensions can be mea-

sured in the laboratory. Characteristics related to market-

ing effectiveness need to be evaluated by users and

potential users of a brand—preferably before the package

is put into production. A variety of marketing research

methods is used for this evaluation.

Figure 4. Use of a pressure-sensitive tape from a pad to close a

mailing envelope.

1198 TESTING CONSUMER PACKAGES FOR MARKETING EFFECTIVENESS

MARKETING RESEARCH OPTIONS

Most research options fall into three broad categories:

Analysis of existing information

Original qualitative research

Original quantitative research

Analysis of Existing Information. An analysis of existing

information is often undertaken at the start of a package

development program. It can be an important ﬁrst step

because it assures that subsequent surveys will add to,

rather than duplicate, information.

The information is drawn from public sources such as

government, trade groups, and publications; from past

studies completed within the organization (especially

tracking studies which reveal changes in consumer beha-

vior); from syndicated surveys (sponsored and conducted

by a research company that sells the results to any

company willing to pay for the information); and from

customer- and consumer-contact records. (In large pack-

aged-goods companies, consumer-contact information is

available daily, and it is often the ﬁrst clue to product and

packaging problems, changing consumer concerns, deﬁ-

ciencies in instructions for use, etc.).

The information obtained is summarized and analyzed

in a report that contains conclusions about the nature of

the market and recommended packaging objectives—cri-

teria or goals that the package must satisfy. The objectives

guide the development program and are used as standards

for judging packaging effectiveness.

Qualitative Research. When people talk about ‘‘qualita-

tive research,’’ they are referring to studies among small

samples of current and/or prospective users of the brand.

These people are interviewed in depth, either individually

or in a group. The research is diagnostic, that is, explora-

tory or directional, and its purpose is to obtain early

indications of packaging problems and opportunities.

In the individual interviews, one person is questioned

at a time using a predetermined question guide (list of

subjects to be covered), or a questionnaire that includes

mostly open-ended, rather than closed-ended, questions.

(‘‘How do you feel about the New York subway system?’’ is

an open-ended question. An example of a closed-ended

question is ‘‘Compared with other forms of public trans-

portation, do you think the New York subway system is

better, about the same or not as good?’’).

The group interview is called a ‘‘focus-group session’’

and is conducted with 8 to 10 people. Questioning is in the

form of a discussion that is led by a trained leader or

moderator who covers subjects listed in a predetermined

discussion guide. Each of these qualitative research tech-

niques has certain advantages:

During individual-depth interviews, information is ob-

tained, and feelings are explored in detail. Each

person expresses his/her opinions and interpreta-

tions without reference to the ideas of others so

there are clear indications of individual preferences

and understanding.

Participant interaction in focus group interviews pro-

vides a rich, multilayered accumulation of informa-

tion and feelings about the subject being discussed.

Comments made by one person may remind others

of points they had not thought of. Each idea ex-

pressed suggests other ideas. Normally, the discus-

sion results in a group consensus.

Both approaches are helpful in the early stages of an

investigation, or as an aid to informed judgment. Indivi-

dual-depth interviews are recommended for early trial, or

where there are questions about consumer understanding

of how a package works, packaging copy, or communica-

tion of ideas. Group interviews are recommended to gain

insights about a broad range of feelings and opinions, as

well as to identify the language or terminology consumers

use to talk about the package and product.

Qualitative research is usually used to develop instruc-

tions for use, create hypotheses and questionnaires

for larger studies, or get initial indications of opinions

and ideas about products, packages, or product/package

combinations.

Quantitative Research. ‘‘Quantitative studies’’ are con-

ducted to obtain deﬁnitive information for decisionmak-

ing. This type of research can take many forms but is

characterized by sample sizes where enough people are

interviewed, so results can be analyzed using statistical

techniques. The interviews may be conducted in person,

by mail, online, by computer, or via video. Certain kinds of

packaging studies are conducted by telephone, for exam-

ple, surveys to determine how and where products are

stored and used, or to deﬁne the target market (the

intended buyer/user).

Questionnaires for quantitative studies usually include

more closed-ended, than open-ended, questions. The ques-

tions are structured to permit various kinds of statistical

analyses that will aid in interpreting the results.

PACKAGING EVALUATION

In considering its marketing effectiveness, management is

most likely to question the degree to which a package

meets three types of goals, and these are the ones most

often subjected to some kind of survey research evalua-

tion: functional effectiveness, visual impact (visibility and

shelf attention), and communications effectiveness (brand

and product identiﬁcation, and imagery).

Testing Functional Effectiveness. Functional effective-

ness is easier to evaluate than the other marketing

dimensions. Some aspects can be handled in the labora-

tory;

others, through

product-testing techniques such as

one-time or multiple-use tests; others, through individual-

depth or focus-group sessions, depending on the nature of

the product and the package.

With few exceptions, product users can be questioned

directly about whether a package is easy to handle, open,

close, store, and use, and whether it might protect the

contents over a period of time. The sample of potential

TESTING CONSUMER PACKAGES FOR MARKETING EFFECTIVENESS 1199

brand users interviewed should include people who use

the product in different ways, those in a mix of age groups

(from children through seniors depending on use), people

of various ethnic backgrounds, as well as those with a

variety of physical characteristics (left or right handed,

have smaller or larger hands, etc.).

It is a given that packages must protect the contents.

But it is also true that the user must believe that the

package really does this. The inner, outer and overwrap

for many over-the-counter (OTC) remedies, as well as

premium food and beauty-aids products are technically

unnecessary. However, proposed substitutes intended to

reduce packaging costs are often rejected by consumers,

primarily because of perceived differences in product

protection.

Depending on the nature of the product and package

involved, an in-home or at-work trial study may be con-

ducted among people in several geographic areas. Where a

totally new packaging concept is being tested, such as the

early versions of aseptic containers for foods, the study

may be restricted to people in areas closest to manufactur-

ing facilities because the samples have a short storage life.

Those people who agree to try the product are inter-

viewed to obtain their initial reactions about its appear-

ance, anticipated beneﬁts and drawbacks, and general

expectations. The product may be tried at that time, or

left for use later, with an evaluation sheet to be completed

immediately after trial. If needed, follow-up interviews

can be conducted by telephone the next day.

Testing the Effectiveness of Graphic Design. Although,

the physical package can be evaluated using product-

testing techniques such as the ones described above,

different approaches are needed to determine the effec-

tiveness of packaging graphics.

Extensive evidence suggests that overall surface de-

signs including words are primary contributors to the

marketing effectiveness of a package. If you think of

packaging as the environment for a product, it is easier

to understand its effect. The tray used for a frozen entre

the baking pan included in a mix, a plastic or glass bottle,

a composite or metal can, a see-through or foil pack;

words, colors, illustrations and over-all design of the

container or label; all of these factors inﬂuence consumer

expectations of, and satisfaction with a brand.

In all studies that involve packaging graphics, the

physical appearance of the test and competitive packages

must be equal. An apparently unﬁnished mockup or one

that is custom ﬁnished should not be shown with printed

competitive packages. The difference ﬂags the package in a

way that biases results. In addition, if the test versions are

potential alternatives for an existing package, the sample

of people interviewed should include enough current users

of the brand to analyze their reactions separately.

In general, graphic design can be evaluated in regard to

the following three aspects: visual or shelf impact, com-

munications effectiveness, and aesthetic appeal.

Visual or Shelf Impact. The most elusive and difﬁcult

packaging aspect to measure is visual or shelf impact. The

questions to be answered include the following:

1. When people shop the product category, does the

package call attention to the brand?

2. As people shop for other types of product, is the

package creating an in-store presence that will

enhance familiarity with the brand?

3. When the buying decision has been made before the

store visit, does the package make the brand easy to

ﬁnd?

To date, there are no research techniques that fully

answer these questions, primarily because visual percep-

tion involves a complex relationship between the structure

of the eye and the functioning of the mind. For example,

seeing is selective. Regardless of where or how the eye

moves, people ‘‘screen out’’ elements they consider irrele-

vant and focus on the familiar. In a visibility test, this

familiarity bias usually produces a higher score for the

current package than for a new package, and for an

established brand than for a new one.

In addition, the effects of demonstrated visual ‘‘enhan-

cers’’ such as high contrast, size, and color density are

predictable. This makes it possible to design for the test,

which produces an apparent ‘‘winner.’’ The most commonly

used methods for testing some aspects of visual impact are

a shopping test, a T-scope (tachistoscope) or controlled-

exposure test, and an eye-movement test of single or multi-

ple packages in a competitive environment. To some degree,

all of these techniques are deﬁcient, but the shopping test

comes closest to indicating what might happen in a store.

In a shopping test, a rough approximation of the in-

store environment is reproduced with actual packages on

shelves in a central interviewing facility, on a videotape, or

on a computer screen. The product arrangement is delib-

erately structured to give all the test brands an equal

opportunity to be noticed, and study participants are free

to look at what interests them and to ignore what does not.

Where an actual product display is used, people can

‘‘shop’’ the shelves and view the packages in motion at

their own pace. They can pick up and examine packages to

gain more information about the brand. Whereas shop-

ping

tests using videotape

and computer simulations are

easier to administer, they have some drawbacks: people

are seated in a quiet room and concentrating, there may

be color and copy distortion due to the limitations of

photography, and the product display is ‘‘framed’’ so that

some of the normal in-store confusion is reduced.

In the controlled-exposure test, the length of time

people can view a picture of a package or shelf display is

limited. A device called a tachistoscope or T-scope is

attached to the lens of a projector. Operating like the

shutter of a camera, it controls the amount of time that a

picture is shown (in fractions of a second). Each exposure

is shown at an increasing amount of time. After each one,

people are asked what they saw.

The controlled-exposure method of testing visual as-

pects of packaging is a speed test. It measures how quickly

something is seen, and it has several drawbacks: People

are concentrating on a stationary picture that organizes

1200 TESTING CONSUMER PACKAGES FOR MARKETING EFFECTIVENESS

the display, and there may be photographic distortion. For

new brands, the interpretation of results is strictly limited

to how easily the brand name is read. For established

brands the test offers a measure of recognition as well as

readability.

T-scope test scores have limited application but can be

helpful in cases where pictures must be used. Some exam-

ples are as follows: to develop indications of differentiation

within a line of products, to test custom-designed containers

where several alternative models are being considered, and

to provide indications of recognition elements when a rede-

sign is being considered for an established brand.

In an eye-movement test, the respondent controls the

length of time the picture will be viewed. A device records

where the eye moves and where it stops over the surface of

the picture. The results are evaluated on the basis of this

record. In addition to drawbacks related to the test

environment and possible photographic distortion, this

method provides information about where the eye travels

but not about what the brain absorbs.

Regardless of the method used, visual-impact scores are

rarely used as a basis for accepting or rejecting a package.

Packages that score well in a visibility test but do not meet

communications objectives are not usually adopted. How-

ever, when communications objectives are met but the

visibility score is low, a package is often selected, although

graphics may be modiﬁed to enhance visual impact.

Communications Measurements. Most packaging tests

include communications measurements. Designers can

predict the visual effectiveness of a package based on

their knowledge of the physiology and psychology of

seeing. However, they ﬁnd it more difﬁcult to determine

the package’s communications effectiveness (the ideas the

package suggests about the brand).

Packages have a substantial impact on people’s ideas

about products and brands. To measure this impact,

research methods and exhibit materials used need to be

appropriate for the product and the particular packaging

design problem, as well as economically feasible. There

are many options for testing package communications,

and no standard techniques or series of techniques.

Most package communications studies evaluate the

brand in relation to competition, and measure several

packaging aspects. Some of the more popular approaches

are as follows:

1. Experimental design matched samples of potential

users are interviewed about one or two competitive

brands, as well as the test brand in one of the

package designs. Questioning and test procedures

are identical so that differences in results can be

attributed to the different packages. Within this

framework, the most often used approaches are as

follows:

a. Brand expectation study, which measures im-

pressions of the brand on the basis of package

appearance

b. Brand trial study, which measures brand and

package performance on the basis of a single trial

c. Location use test which measures brand and

package performance in-home or in the work-

place on a one-time or multiple-use basis.

2. Product formulation/structure study, which treats

each package as a separate formulation or struc-

tural version of the brand and determines perceived

differences.

Aesthetic Appeal. If the purpose of the study is to

measure aesthetic appeal, consumers are asked to rank

proposed packages in regard to how attractive they are.

CONCLUSION

In addition to standard speciﬁcations for conducting use-

ful surveys, the following are the primary requirements

for conducting research to evaluate the marketing effec-

tiveness of packaging:

1. The packaging dimensions of interest need to be

measurable. Subtle differences in graphic design

and some packaging objectives (such as ‘‘generate

trade excitement’’) cannot be measured.

2. Study objectives should be stated clearly in writing,

related to the packaging objectives, and indicate the

kind of information to be obtained and how it will be

used.

3. The study plan must be capable of yielding the

information speciﬁed in the objectives.

4. Action standards should be established in advance.

These standards provide a common framework for

judging study results by indicating the order of

importance of each measurement used and the

research criteria to be met.

5. The people interviewed need to be capable of provid-

ing meaningful information.

6. Alternative test packages must be equally accepta-

ble to management. If, for any reason, a package

cannot be adopted, then it should not be included in

the test.

7. Exhibit materials need to be appropriate and

equivalent to avoid biasing results.

8. When developing packaging communications infor-

mation, the tester is measuring how the package

inﬂuences ideas about the brand. This means people

must be asked about the product and brand before

any direct questions about

the package.

9. Package designers and developers should be in-

volved in the research to be sure that the study

plan is compatible with the packaging objectives, to

control the appearance of exhibit materials and to

add valuable insights in explaining or interpreting

test results.

In conclusion, the package is an integral part of most

brands and can provide a competitive marketing edge.

Successful package development is the result of careful

consideration of alternatives. As each packaging decision

TESTING CONSUMER PACKAGES FOR MARKETING EFFECTIVENESS 1201

is made, it narrows the options to be considered at the next

step. Survey research assures that choices will result in a

package with maximum marketing effectiveness.

TESTING, PACKAGING MATERIALS

PATRICIA D. GUERRA

MARCONDES

DUNCAN O. DARBY

Clemson University, Clemson,

South Carolina

INTRODUCTION

The need to test packaging materials and components

may arise for a variety of reasons. Maintaining production

standards is the most common one. Verifying that the

material will perform in a new application might be

another. When a problem is identiﬁed and the source is

unknown, investigative tests, both qualitative and quan-

titative, are often needed.

It is helpful to think of packaging materials testing as a

function of factors such as packaged product class, pack-

age component, and package function, as these factors

may determine the types of tests necessary. Product

protection is a package function that leads to tests such

as drop and vibration. Certain package components need

to comply with industry-deﬁned dimensional standards.

Products such as food, drugs, medical devices, and hazar-

dous materials are highly regulated, so the packages that

contain these products are also regulated.

This article is organized by material: plastic, paper

(including paperboard and corrugated), metals, glass, and

wood. Many other materials are used in packaging, and

many containers, which are available, include components

made of different materials. An effort was made to include

these components and their related testing under the

materials discussion.

REGULATORY AGENCIES AND STANDARDS

ORGANIZATIONS

In the United States, the Food and Drug Administration

(FDA) is charged with safeguarding the quality of pro-

ducts destined for human consumption. There are many

ways in which the quality of foods, pharmaceuticals and

medical devices can be adversely affected by packaging

issues. Packages may not be correctly closed. Tears, holes,

and cracks can occur that allow the product and the

environment to interact. Packaging materials and compo-

nents might be a source of indirect additives through the

migration of chemicals through the package into the

product. The directives guiding packaging of these classes

of products are found in the Code of Federal Regulation,

Title 21 (CFR 21). It is common for the FDA to recognize

standards from consensus-based standards organizations,

such as the International Standards Organization (ISO)

and/or ASTM International, for the measurement of com-

pliance with these objectives.

When the package function is protection from transpor-

tation hazards, the National Motor Freight Classiﬁcation

Committee (NMFC), the Department of Transportation

(DOT), and the International Civil Aviation Organization

(ICAO) regulate the types of materials that may be used for

different product classes and the standards that these

materials must meet. The International Safe Transit Asso-

ciation (ISTA) in the United States has a set of standard

procedures for testing the performance of shipping contain-

ers for a variety of shipping environments and products.

ASTM International has developed test procedures that

prescribe how testing should be conducted for a variety of

properties of a variety of materials used for packaging,

including performance during transport. The ASTM tech-

nical committee D10 deals speciﬁcally with developing

standard procedures for testing packaging materials and

components. Other ASTM International technical commit-

tees also have jurisdiction over areas of interest to packa-

ging professionals in terms of testing, such as committee

F02 on ﬂexible barrier packaging and committee D06 on

paper and paper products. The Technical Association of the

Pulp and Paper Industry (TAPPI) also offers standard

procedures for testing pulp and paper materials, including

paperboard and corrugated. In some cases, there is some

overlapping in standards from ASTM, TAPPI, and ISO. It is

up to the packaging professional to identify the one that is

mostly accepted by his or her sector of the industry.

In addition to the already mentioned federal regulatory

agencies, packaging professionals must also be aware of

state and even local regulations. Because regulations

change over time and from state to state and country to

country, it would be impractical to cover every one in an

encyclopedia. This article attempts to make the reader

aware that these exist and that every packaging profes-

sional should be familiar with the ones that pertain to his

or her sector of the industry and distribution cycle.

PLASTICS

Plastics are widely used in ﬂexible, semirigid, and rigid

packages. Polymer ﬁlms are used alone or in multilayer

structures in the form of bags, pouches, and overwrap

ﬁlms to name a few. Rigid plastic containers are also

common in the form of jars, drums, pails, jugs, bottles,

trays, and others. Foamed polymers may be used for

protection against drops and vibration and for tempera-

ture control. Woven plastic ﬁbers are used in large

packages of relatively heavy products, such as dry pet

foods and industrial goods. Nonwoven ﬁbers are a common

component of medical device packaging.

Several fundamental plastics properties are used to

characterize and compare plastic materials used in packa-

ging applications. This includes thermal transition proper-

ties, such as the glass transition temperature (for

amorphous and semicrystalline plastics), and the melt

point (for semicrystalline plastics). For semicrystalline

plastics, the percent crystallinity may also be estimated.

1202 TESTING, PACKAGING MATERIALS

Measurement of these properties is best conducted with

thermal analysis equipment such as differential scanning

calorimetry (DSC). Other thermal analyses, including

thermo-gravimetric analysis (TGA), thermo-mechanical

analysis (TMA), and dynamic mechanical analysis

(DMA), may also be used to characterize how plastic

behavior changes with temperature. Melt ﬂow properties,

such as melt ﬂow indices, melt ﬂow rates, melt viscosities,

melt strength, and so on, are predictors of performance on

package-manufacturing equipment, as well as of perfor-

mance in the ﬁeld.

Datasheets that include the basic characteristics of

ﬁlms and other ﬂexible plastics are available from suppli-

ers and include basic information such as yield, gas-

barrier properties, gauge, tensile strength, optical proper-

ties, and dimensional stability. Table 1 lists some of the

more common properties of ﬂexible plastic materials. Most

of these properties are discussed in detail in other sections

of this encyclopedia. Properties of multilayer materials

are also included in Table 1.

It is important to test the properties in Table 1, because

they have a direct inﬂuence on how the individual materi-

als will perform as part of a package system. This includes

how a material will work on the machinery that converts

it into a package, and how it will interact with the product

it contains.

The weights of substrates, coatings, inks, adhesives,

and sealants are usually measured on a certain size

specimen, and the overall weight is extrapolated from

that. Weight is often measured per area of ﬂexible

substrates, and the term used for this is basis weight.

The basis weight is usually speciﬁed for the product to

perform the desired function.

The uniformity of a substrate’s thickness is important. A

lack of uniformity may lead to variations in other test

results, such as permeation rates and tensile strength, and

it may interfere with performance on the packaging line or

in the ﬁeld. A certain amount of variation may be accepted.

Several measurements are taken and values are averaged.

For multilayer applications, the strength of the adhesion

between layers is evaluated to make sure that the layers

will hold together for the intended applications. The force

necessary to separate the layers is measured and compared

with the minimum speciﬁcation for the application.

Knowledge about the strength properties such as ten-

sile, puncture, tear, and so on are helpful in selecting

materials for ﬂexible packaging. This selection is based on

application and hazards that the product is likely to

encounter in its lifecycle. Actual data from these tests

doesn’t always apply directly to an application, but it may

still prove helpful in comparison of materials.

Surface properties impact the ability of materials to

stick together and ﬂow over machinery. For ﬁnished

packages, these properties impact the stacking stability.

Minimum treatment levels are speciﬁed for materials

used in printing and laminating applications. Films may

not track well on packaging machines when the coefﬁcient

is too low or too high. Large bags of products such as pet

food or industrial products must meet a coefﬁcient of

friction range to prevent sliding when stacked.

The outside of packages is often part of the marketing

effort for a product. Therefore, the aesthetic appearance of

materials is important. Visual properties such as gloss can

add value from a marketing perspective. Print quality is

another important factor that is measured and tracked in

various ways all the way from the printing plant to the

store shelf. There are regulations on type size and legibility

for certain information communicated to the consumer in

industry sectors such as food and drugs. Colors can also be

measured. Many of these properties are measured using

the naked eye, or instrumentation, or both.

Opacity is also a visual property of materials. The

amount of light transmitted through a packaging material

may accelerate deteriorative reactions in food products,

for example. There is more than one way to express

opacity. It may be done in terms of optical density or light

transmittance. Metalized materials are often compared

based on these parameters.

It is often necessary to control the atmosphere within a

package. For example, too much or too little oxygen

impacts the shelf life of many perishable products. Thus,

the tendency of gases to move through the package

materials must be understood and measured. The most

common permeants are listed in Table 1. Please see the

permeability section of this encyclopedia.

Organoleptic tests involve qualitative and quantitative

tests to verify that packaging materials or their additives

do not adversely affect the ﬂavor of products. Panels of

humans trained to detect solvent odors are routinely used

to evaluate packaging materials as they are made. Food

companies often use sensory panels to study product/

Table 1. Flexible Plastic Material Properties

Weight (coatings, adhesives, and sealants)

Thickness (gauge)

Adhesion (adhesive to substrate, inks to substrate, extrudate to

substrate, coextruded layers)

Strength

. Tensile

. Puncture

. Tear resistance

. Burst resistance

. Impact resistance

. Flex resistance

Surface

. Surface energy (contact angle)

. Friction [coefﬁcient of friction (COF), ﬁlm to ﬁlm, and ﬁlm to

steel]

. Abrasion

Visual/optical

Gas barrier (transmission rates)

. Oxygen

. Water vapor

. Carbon dioxide

. Nitrogen

. Flavors/aromas

Organoleptic (retained solvents and other volatiles)

Shock and vibration Transmission (foams)

TESTING, PACKAGING MATERIALS 1203

package ﬂavor interactions. These activities are typically

combined with analytical instrumentation such as gas

chromatography, microbial analysis, color measurement,

and so on.

Foams placed inside or outside of primary packages

protect by absorbing part of the energy of an impact.

Different densities of foam and different materials (poly-

styrene vs polyethylene, for example) offer different levels

of protection (see Cushioning, design section for more

information).

Table 2 includes a selection of tests that are commonly

performed on packages to evaluate their performance. In

addition to these, some properties of the resins such as

melt index and ﬂow rates are also measured.

In most plastic packages, the closure system is essen-

tial to the package’s performance. Closing the package

assures that the package is allowed to perform its func-

tions, by keeping the product within the package and also

preventing exchange of the package’s atmosphere with

that of the outside environment. In many plastic packa-

ging applications, closure is achieved by creating a ther-

moplastic seal. The seal strength can be measured to help

predict the ability of the package to survive its lifecycle

and to assess the force or energy required to open the

package. In the hot tack test, the seal strength is mea-

sured immediately after the seal is made to predict the

ability of the packaging material to contain the product

when it is hot. This property is useful in predicting

performance on the packaging machine or in cases where

the product is ﬁlled at an elevated temperature. See

section Seal, heat for more detailed information.

Other tests may be needed to verify that the package

was successfully sealed throughout the seal perimeter and

that it will not leak or open prematurely in the distribu-

tion cycle. Tests used for seal integrity include burst tests,

dye leak tests, pressure or vacuum decay tests, and many

others. Simulated or actual shipping tests may also be

run, either as a standalone method to check the package

integrity or to verify that the seal integrity tests chosen

correlate to reality.

Burst tests on packages may be run not only for seal

integrity testing but also to verify that the package has

the strength to be stacked and dropped in the distribution

system.

Dimensions, dimensional consistency, and dimensional

stability of packages are important for space usage, pro-

cessibility on packaging machines, and for aesthetic con-

siderations. Packages must consume the correct amount of

space when stored, shipped, and on the shelf in the

marketplace. Internal dimensions must be consistent to

assure that the net weights or volumes on packages are

correct. Automated packaging machines often require

speciﬁc tolerances on the package dimensions to facilitate

the desired productivity. Dimensional stability must be

maintained during thermal processes, such as retorting

and autoclaving. Packages must resist deforming dimen-

sionally to assure that the packages remain closed and

present an attractive marketing message to the consumer.

Chemical resistance is an important consideration and

is one of the reasons that we ﬁnd chemicals packaged in

several different packaging materials. The packaging

materials must offer chemical resistance to the compo-

nents of the product as well as from any outside elements

that might come in contact with the package.

When a package is designed with the expectation that

it will bear some or the entire load in a stacking situation,

that package must be evaluated for its stacking strength.

In many cases, the products can bear the load.

PAPER, PAPERBOARD, AND FIBERBOARD

Paper is used as a layer in multilayer structures (some of

these are various layers of paper, others include coatings,

ﬁlms, and foils) and it is also used on its own. Paperboard

is converted into cartons and boxes that can function as

primary, secondary, or tertiary packages.

Corrugated ﬁberboard is made of linerboards and a

corrugated medium. Once it is converted into boxes, it is

required to carry a box manufacturer certiﬁcate listing the

burst strength or the edge crush test (ECT). Both certiﬁ-

cates also list the size limit and gross weight limit.

Another common use for corrugated in packaging is trays

(Table 3).

Table 2. Container Properties (Rigid and Flexible)

Sea

. Hot tack

. Seal strength

. Integrity (cracks, tamper evidence, child-resistant features)

. Burst

Barrier

. Oxygen

. Water vapor

. Carbon dioxide

. Nitrogen

Dimensional consistency and stability

Chemical resistance

Stacking strength

Table 3. Materials and Container Properties

Basis weight

Strength

. Tensile

. Tear resistance

. Puncture resistance

. Burst (mullen)

. Edge crush (corrugated ﬁberboard)

. Flat crush (corrugated ﬁberboard)

. Folding endurance

. Structural design performance (ﬁnished containers)

Moisture resistance

Permeability (body of composite cans)

. Oxygen

. Water vapor

1204 TESTING, PACKAGING MATERIALS

Like plastic materials, paper and paperboard are often

speciﬁed and ordered in terms of basis weight, so this test

can conﬁrm that the material at hand conforms with the

order, for example.

As with other packaging materials, the strength proper-

ties of paper, paperboard, and corrugated are important for

matching the materials to the packaging application being

considered. For example, the results of a tear resistance test

are an indication of how a material might perform in an

application that requires windows or other cutouts.

The burst resistance test is done to ﬁnd a board’s ability

to withstand external and internal pressures. It is not

considered the best way to evaluate double- or triple- wall

corrugated boards. Flat crush is used to evaluate those

boards.

Structural design performance tests evaluate the ability

of the erected container to perform from the time it is put

together to when it reaches the ultimate user. These tests

are designed to simulate various shipping and distribution

cycles in terms of shock, vibration, and compression A

container might be exposed to moisture in several ways.

It may come from the outside as rain, or it may come from

the packing environment in the case of washed vegetables

for example. Depending on the application, it is important

to measure the impact of moisture on paperboard and

corrugated ﬁberboard properties to assure that they will

perform correctly for the packaged product and distribution

environment.

METALS

Steel and aluminum are used to make containers and

components, such as cans, drums, trays, and caps. Steel

cans are widely used in applications such as processed

foods, chemicals, and paint. Steel containers and con-

tainer components such as caps are also found in packa-

ging systems for foods, cosmetics, consumer goods, and

industrial goods. Aluminum is used in the form of foil (less

than 0.006 in. thick), as a layer in multi-layer structures,

and as trays in frozen foods and preserves. It is also

converted into cans and bottles used for beverages, food,

and cosmetics. Metalized materials are produced by va-

cuum deposition to create a thin light and gas barrier onto

substrates or formed packages.

Metal for packaging uses often begins in the molten

form. Then, it is cast into either ingots or thick sheets.

Ingots will subsequently be rolled into thinner strip

metals in the hot rolling process and wound into coils.

Cast metal sheets are rolled into coils as a part of pro-

cessing. More reductions in thickness are achieved by cold

rolling. In the case of foils, the rolling will continue down

to thicknesses around 6 microns. Rigid metal packaging

such as cans are made from either coils or cut sheets.

Although steel packaging is mostly iron and aluminum

packaging is mostly aluminum, other alloying metals at

varying concentration actually provide many properties

we depend on for packaging applications (Table 4). Addi-

tionally, processing has a signiﬁcant effect on the grain

structure of metals, which also have a signiﬁcant effect on

the ﬁnal package properties. Thus, effective measurement

of metal properties may include the measurement of

concentration and of grain size measurement.

As in all packaging materials, cost is a key factor. Thus,

basis weight and thickness are monitored in the produc-

tion of sheets, coils, and ﬁnished metal packages.

The substrate materials may endure processing, such

as washing coating and printing, in the sheet form before

being formed into packages. In other cases, some of these

processes may occur on the shaped package rather than on

sheet form. Plating with another metal may also be used

for corrosion resistance or for other properties. In each

case, it is important to measure the adhesion and basis

weights of coatings or platings.

The mechanical properties of these metallic materials,

such as tensile/compression strength, are routinely mea-

sured in the production and use of metals. As in plastics,

these properties can serve as either direct measures of

predicted performance, or as relative measures for compar-

ison. Most metal packaging is formed at temperatures that

are relatively low compared with the metal’s melting point.

Thus, it is important to understand the ductile properties

of the metals used. Measurement of formability and ducti-

lity properties, beyond those found in the tensile test, may

be required. For example, Rockwell hardness testing can be

used with evaluate the temper of steel cans. Denting of

cans is considered to be a defect in some cultures, and it can

reduce the can’s axial strength, so denting resistance may

also be measured. Many cans are subjected to signiﬁcant

pressure ‘‘events,’’ such as sterilization for canned foods or

the pressure effects of containing carbonated beverages.

Pressure testing is required to assure that the package can

withstand these events.

Some cans are rolled pieces of sheet that are welded

together at the overlap of the metal, which is called the

seam. Cans are inspected to make sure that the seams are

hermetic to ensure the sterility of the product. For a

variety of reasons, the casting and rolling processes can

Table 4. Materials and Container Properties

Chemical makeup of alloy

Grain size

Basis weights

Thicknesses

Coating/plating basis weights

Adhesion of coatings/platings

Strength

. Tensile

. Stacking strength

. Hydraulic pressure strength

Package integrity

. Pinholes

. Weld quality

. Leak testing

. Permeability

Visual/optical

. Surface reﬂectance

. Aesthetics

Dimensions

TESTING, PACKAGING MATERIALS 1205

result in tiny holes in the aluminum sheets or foil. These

holes, which are referred to as pinholes, can be viewed by

the naked eye or by using automated optical comparator

systems. Leak testing systems are also used to verify the

integrity of cans. Most metals are largely impenetrable by

most common permeants. Thus, metals are used in cases

where absolute barrier is needed. However, thin-gauge

aluminum foils (below 20–25 micron) may have pinholes

present, and metalized ﬁlms seldom have sufﬁcient metal

for an absolute barrier to exist. In these cases, gas barrier

permeability evaluations can be conducted.

As with other packaging materials, the visual appear-

ance of metallic packaging is sometimes an important

factor. Because metals can be highly reﬂective, reﬂectance

values are sometimes speciﬁed. Metallic packaging is

often printed, so print quality is also an important prop-

erty. Metalized ﬁlms are tested for optical density and/or

light transmission to ensure the needed opacity has been

achieved during the metallization process.

Dimensions for metal cans and bottles are important to

assure proper space consumption, proper ﬁlling capacity,

and processibility on high-speed ﬁlling lines. Metal caps

for bottles, jars and cans also have to conform to dimen-

sional requirements for the ﬁlling and capping process to

occur at the speeds required by the production equipment,

as well as to assure that the package is hermetic.

GLASS

Bottles, jars, and jugs and ampoules made of glass are

used in the industry for food and pharmaceutical packa-

ging. Glass packaging is usually formed directly from the

molten raw materials into the package. This means that

material testing generally must be conducted on the

package itself rather than on a sheet or resin pellet as is

an option in papers, metals, and plastics. Most standards

have to do with maintaining production quality and

dimensional consistency (Table 5).

Glass properties are dependent on the composition.

Appropriately equipped analytical laboratories can deter-

mine this, but in glass manufacturing plants, density and

softening point can be substituted for a full analysis.

Strength in glass is not typically measured using a

tensile strength as in most other materials, because it is

extremely strong but extremely brittle. Compressive

strength measurements of glass result in much higher

strength values than tensile strength measurements.

Glass packages generally break at lower values than

the theoretical expectations because of small cracks on

the surface that serve as stress concentration points.

Online application of pressure, at squeezing stations on

glass package-making lines, is used to prevent cracked,

broken, or weak packages from advancing into the pro-

cess. Internal pressure resistance is an important prop-

erty of glass containers, which will endure pressures

such as sterilizing in the package and carbonation. The

compressive strength of glass packages reﬂects their

ability to support the load in stacking systems and

when closures are applied. It is generally addressed

during the design stage by selecting appropriate neck

and body diameters and shoulder radius. The heel design

of containers can also improve strength.

Thermal shock is a measure of glass’ tendency to crack

under heat. This is important for hot ﬁll, retorting, and

applications in which the product is heated in glass by the

consumer to be served. Finite-element analysis is used to

model this.

Glass is often used for its superior optical properties.

Thus, measurement of these properties is important. On

glass production lines, automated inspection stations are

used to verify that the containers are free of sand, dirt,

stones, and other visual defects. Clarity and color, and the

consistency of both, are important in glass manufacture

and use. When printed or when graphics are formed into

the glass surface, the appearance of these aesthetics also

needs to be measured.

The containment capability of a glass container is

dependent not only on the properties of the particular

glass formula but also on the thickness of the container

walls. Additionally, the total weight of each container

must be measured and controlled to assure consistency

of cost, performance, and ﬁll weights. The ﬁnish dimen-

sions must be consistent to assure that the cap/closure

system ﬁts properly, offers correct opening strength, and

provides an appropriate seal of the package.

Glass offers excellent water vapor and gas-barrier prop-

erties. When pigmented, it provides light control as well.

WOOD

Wood is an important packaging material that is speciﬁ-

cally used for pallets, crates, and boxes used in transport

packaging. A limited amount of testing is conducted on the

wood materials themselves, but in the construction of wood

packaging, moisture content and shrinkage properties are

speciﬁed. In the case of pallets, tensile properties are

seldom measured, but compression and ﬂexural properties

(strength and moduli) are both important for the

Table 5. Materials and Container Properties

Composition

. Composition

. Density

. Softening point

Strength

. Compressive

. Stacking strength

. Hydraulic pressure strength

. Impact strength

Thermal shock

Visual/optical

. General visual quality

. Clarity

. Color

Dimensions

. Container weight

. Wall thickness

. Finish dimensions

. General dimensions

Permeability

1206 TESTING, PACKAGING MATERIALS

application. These are generally controlled through selec-

tion of woods that deliver the desired performance at the

best cost.

CONCLUSION

Entire books could be written about testing systems for

each of the packaging materials/package types outlined

above. This article has been written to attempt to brieﬂy

describe that what and the why involved in packaging

material testing. The reader is encouraged to review the

references as well as the individual sections elsewhere in

this encyclopedia.

Ideally, the package is developed along with the pro-

duct and adjustments are made along the design and

development stages to provide the best ﬁt between pack-

age and product. Packaging is usually a system, so even

though testing the individual components is a good start-

ing point, it does not exclude the need to test the package

system as whole at every stage of the product cycle from

the time it is packaged to its ultimate use.

BIBLIOGRAPHY

ASTM International.

Brockway Glass School, Brockway, Inc., New York, 1987.

A. L. Brody and K. S. Marsh, eds., The Wiley Encyclopedia of

Packaging Technology, 2nd edition, John Wiley & Sons, Inc.,

New York, 1997.

W. D. Calister, Jr., Materials Science and Engineering An Introduc-

tion, John Wiley & Sons, Inc., New York, 1940; 7th ed., 2007.

J. Cavanagh, ‘‘Glass Container Design,’’ in A. L. Brody, K. S.

Marsh, eds., The Wiley Encyclopedia of Packaging Technology,

2nd edition, John Wiley & Sons, Inc., New York, 1997.

J. Cavanagh, ‘‘Glass Container Manufacturing,’’ in A. L. Brody,

K. S. Marsh, eds., The Wiley Encyclopedia of Packaging Tech-

nology, 2nd edition, John Wiley & Sons, Inc., New York, 1997.

Code of Federal Regulations, Title 21. Ofﬁce of the Federal

S. Government Printing Ofﬁce. Washington, DC, 1992.

D. Darby, PKGSC 430 Converting for Flexible Packaging –

Spring, 2009. Clemson University, Clemson, SC. 2009.

National Wooden Pallet and Container Association. Uniform

Standards for Wood Pallets.

Fibre Box Handbook, Fibre Box Association, 2850 Golf Road,

Rolling Meadows, IL.

C. Gaynes, ‘‘Packaging Materials Packaging,’’ in A. L. Brody and

K. S. Marsh, eds ., T he Wiley Encyclopedia of Packaging Technol-

ogy, 2nd edition, John W iley & Sons, Inc., New York, 1997.

Glass Packaging Institute.

J. F. Hanlon, Handbook of Package Engineering, McGraw-Hill,

New York, 1971; 3rd edition, 1998.

O. L. Heck, ‘‘Can Seamers,’’ in A. L. Brody and K. S. Marsh, eds.,

The Wiley Encyclopedia of Packaging Technology, 2nd edition,

John Wiley & Sons, Inc., New York, 1997.

R. J. Hernandez, ‘‘Polymer Properties,’’ in A. L. Brody and K. S.

Marsh, eds., The Wiley Encyclopedia of Packaging Technology,

2nd edition, John Wiley & Sons, Inc., New York, 1997.

B. Johnson and R. Demorest, ‘‘Permeation and Leakage Testing,’’

in A. L. Brody, K. S. Marsh, eds., The Wiley Encyclopedia of

Packaging Technology, 2nd edition, John Wiley & Sons, Inc.,

New York, 1997.

B. Page, Metal Packaging, Pira International, UK, 2001.

G. C. Phillips, A Concise Introduction to Ceramics, Van Nostrand

Reinhold, New York, 1991.

J. E. Shelby, Introduction to Glass Science and Technology, The

Royal Society of Chemistry, UK, 2005.

G. L. Robertson, Food Packaging, Principles and Practice, Marcel

Dekker, Inc., New York, 1993.

Steel University.

D. Twede and R. Goddard, ‘‘Packaging Materials,’’ Pira Interna-

tional, UK, 1998.

S. E. M. Selke, J. D. Culter, and R. J. Hernandez, Plastics

Packaging: Properties, Processing, Applications and Regula-

tions, 2nd edition, Hanser, Munich, Germany, 2004.

TESTING, PERMEATION AND LEAKAGE

BERT JOHNSON

ROBERT DEMOREST

MOCON,

Minneapolis, Minnesota

These two factors, permeation and leakage, can have

similar effects on packaged goods, but they are totally

different processes. When oxygen (O

), water vapor (H

O),

carbon dioxide (CO

), odors, and ﬂavors move out of

packages or into other packages, quality is lost, and shelf

life is shortened.

Great strides have been made in permeation, which is a

science relatively unknown to the average citizen, but

leakage, a subject familiar to many, seems to be slower in

developing a universally accepted testing technology.

Testing methods for both permeation and leakage are

discussed here.

PERMEATION

In general, three separate phenomena occur simulta-

neously.

Solubility—penetration into polymer

Diffusion—penetration through polymer

Desorption—evaporation from polymer

The total permeation through the barrier is made up of the

sum total of all three parameters, and it is referred to

metrically as

Permeation rate—(mL mm)/(m

24 h atm), dry, at

(temperature, 01)

Transmission rate—(mL/(m

24 h), dry, at (tempera-

ture, 01)

Note that the transmission rate (TR) has not been normal-

ized for atmospheric pressure or thickness. The laboratory

must decide the best units. However, if the instrument is

equipped with a pressure transducer, so that results are

adjusted to sea level, then it is common to state the TR

TESTING, PERMEATION AND LEAKAGE 1207